The present invention is generally directed to toner and developer compositions, and more specifically, present invention is directed to developer and toner compositions containing novel linear polyester resins, and processes for the preparation and use thereof. In embodiments, there are provided in accordance with the present invention toner compositions comprised of certain polyester resin particles, and pigment particles comprised of, for example, carbon black, magnetites, or mixtures thereof, and/or other colored pigment particles, such as a cyan, magenta, yellow, blue, green, red, or brown components, or mixtures thereof thereby providing for the development and generation of black and/or colored images. In embodiments, there are provided in accordance with the present invention toner compositions comprised of a pigment, and a linear polyester resin of the formula ##STR3## where R' is independently selected from the group consisting of phenylene, cyclohexylene, and alkylene with from 4 to about 24 carbon atoms, where R is of the formula ##STR4## representing either an oxyalkylene group or a condensed mixture of oxyalkylene and diol groups, wherein R" is independently selected from the group hydrogen and hydrocarbon substituents with from 1 to about 24 carbon atoms, n is an integer from about 2 to about 10,000, and m is an integer from about 2 to about 10,000.
In embodiments, there are provided in accordance with the present invention processes for the preparation of the abovementioned linear polyesters and branched polyesters thereof.
The toner compositions of the present invention, in embodiments, possess a number of advantages including low melting characteristics, broad fusing latitudes, excellent blocking characteristics, excellent admix characteristics, are of low cost, and possess excellent non vinyl-offset properties. The toner compositions of the present invention can in embodiments be prepared by conventional condensation polymerization processes, for example, as disclosed in U.S. Pat. No. 5,391,452, and as illustrated herein. The polyester toner resins of the present invention can in embodiments be generated by a process involving (a) melt polycondensation of about 0.9 mole equivalent to about 1.1 mole equivalents of a diol or mixture of diols such as 1,2-propane diol and or a polyoxyalkylene glycol with about 0.9 mole equivalents to about 1.1 mole equivalents of a diacid such as terephthalic acid or diesters thereof such as dimethyl terphthalate, yielding a polyester oligomer or polymer with a degree of polymerization which is readily controlled by the operator, and with a number average molecular weight(Mn) of from about 2,000 grams per mole to about 100,000 grams per mole, a weight average molecular weight(Mw) of from about 4,000 grams per mole to about 250,000 grams per mole as measured by gel permeation chromatography, and polydispersity of from about 1.8 to about 17.
In other embodiments of the present invention, there may be included in the reaction mixture a branching agent in amounts of from about 0.1 to about 5.0 weight percent based on the total weight of the polyester reactant constituents, to provide branched polyester which possess the aforementioned desirable resin properties.